The grisly murder of a U.S. Drug Enforcement agent in Mexico, back in 1985, was a milestone in the decades-long war on drugs. And the horror of that crime resurfaced this past Friday, after a Mexican court ordered the early release of the drug kingpin who masterminded that killing. Rafael Caro Quintero served 28 years of a 40-year sentence.

The White House has reacted angrily to his release, along with reports that another drug lord connected with the case might also be freed.

Los Angeles Times reporter Tracy Wilkinson is covering this story from Mexico City and joins us now. Good morning.

TRACY WILKINSON: Good morning.

MONTAGNE: Remind us of the circumstances of this killing.

WILKINSON: Well, this was a DEA agent based in Guadalajara. His name was Enrique Camarena. He left the U.S. consulate where he was based one day, February in 1985, to go meet his wife for a meal at a restaurant and never returned. The drug traffickers kidnapped him. They tortured him and killed him.

It took several weeks of intense search to finally find his body, along with a Mexican pilot with whom he had worked a lot to hunt marijuana fields; which is basically what Camarena, the agent, was doing here in Mexico.

It was really a line that the traffickers had never crossed before, to actually kill a U.S. federal agent, and it really turned the entire Mexico-U.S. relationship on its head. And it changed - actually forever - it changed the relationship in terms of fighting drug trafficking in Mexico.

MONTAGNE: Well, how so? I mean how did this case fit in to what were joint efforts to stop the illegal drug trade?

WILKINSON: Well, injected a great level of mistrust. The U.S. believed that some Mexican authorities helped the drug lord Quintero to escape temporarily until eventually he was caught in another country. And the two sides just did not trust each other for years.

MONTAGNE: Why did a Mexican court release Quintero now suddenly, 12 years before he should have been released?

WILKINSON: Well, that's a good question. He had appealed to demand his release. This court decided, well, he'd been tried in the improper court. He should have been tried in a state court instead of a federal court, and released him on those grounds. Most legal experts feel that it was a rather specious reasoning, that something else might be at play - we don't know for sure - corruption, the judges bought off.

We don't know, but it's a very suspicious ruling. And it's unclear exactly why this court at this time did this. But it's caused outrage not only in the U.S. but in Mexico as well.

MONTAGNE: So it's not playing very well in Mexico. What does it mean for Mexico's relatively new president?

WILKINSON: Well, it's a problem that he will have to deal with. Even though this was an ostensibly independent court that did it, it's a problem for this government because this is a government that is from the Institutional Revolutionary Party - the PRI, which ruled Mexico for 70 years - and had at the time, its reputation was it had a very cozy relationship with drug traffickers and allowed them to operate in many parts of the country.

And the new president, Enrique Pena Nieto, has tried to say, well, no - this is a new PRI, a new party that is modern and transparent and no longer does those things. And so for him to be in office for barely eight months - and suddenly one of Mexico's biggest drug traffickers is released from prison, it's a political problem that he's going to have to face. Even though, you know, technically his government did not release this man, it is an issue that he's going to have to explain one way or the other.